Optical accommodative compensation system

Abstract

The optical system presents accommodation compensation, the system including in combination two multifocal lenses, one of them being an aperture lens and the other a field lens.

Description

TECHNICAL FIELD TO WHICH THE INVENTION RELATES [0001] The present invention relates in general to compensating or correcting vision disorders, and more particularly to cases in which the accommodation function of the eye is deficient. Concretely, the invention relates to an optical system implemented for compensating this deficiency, and to visual equipment incorporating the system. [0002] Still more specifically, but not exclusively, the invention relates to the field of implanting artificial intraocular lenses, in which case it relates to an optical system for correcting the aphakic eye. TECHNOLOGICAL BACKGROUND [0003] In general, an optical system for compensating or correcting vision can make use of two main types of lens. [0004] An aperture lens is designed to exercise the optical function that gives it its correcting or compensating power either in or against the eye. It is typically an intraocular lens or a corneal contact lens. The optical function exerted on the eye by such...

AI Technical Summary

Benefits of technology

[0026] The object of the present invention is to propose an alternative solution for compensating anomalies in accommodation, that is favorable both to daily comfort in use and that improves the chances of patient adaptation and tolerance, in particular when an intraocular implant is put in the place of the natural lens.

[0029] The invention thus provides a solution that makes possible and requires a reduction in the addition provided by each lens. The optical system of the invention thus shares the overall power addition required by the wearer between the field lens and the aperture lens. This results in an enlargement of the perceived fields and a reduction in distortion. This also results in smaller dependence on the diameter of the pupil, which is particularly advantageous for correcting sight in old-aged patients for whom the pupil often tends to shrink.

Problems solved by technology

Unfortunately, investigation work carried out by the Applicant has shown that the addition strength of a lens needs to be considered as a factor contributing to it being rejected by wearers or at least acting as a brake to wearers adapting thereto.

The drawback is that the aphakic eye loses all natural accommodation power.

Unfortunately, studies carried out by the Applicant have led to the conclusion that in combination with the upheaval constituted by the surgery and the artificial implant itself, particularly in patients who are quite old, wearers find it difficult to tolerate high power progressive lenses.

Unfortunately, such multifocal implants are often found to be a failure, either because visual acuity is insufficient, in particular for reading in the near field, or else because the pseudo-accommodation function of such implants does not operate.

From this state of the art, it can be seen that compensating accommodation disorders leads to a persistent problem of intolerance or at least of difficulty in adaptation of subjects to the correcting equipments or systems that are proposed to them.

The use of progressive field lenses is not always satisfactory either, depending on the wearer's disorder and need for addition.

The continuous progression of spherical power requires a connection, e.g. on the front face of the lens, between a far vision zone of greater radius of curvature and a near vision zone of smaller radius of curvature, and this inevitably gives rise to zones of reduced optical quality, particularly in the side portions of the lens.

This is because any enlargement of the sharp field of vision implies an increase in peripheral distortion, which is troublesome in static vision and above all in dynamic vision; and conversely it is possible to limit peripheral distortion only to the detriment of the fields of view that are sharp, which become smaller.

It will be understood that this problem is particularly difficult and harmful to adaptation by the wearer when the power added by the lens is considerable.

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